Info screen

I have a question which I cannot find the answer to. In the Info Screen (F9) on the graph section, sometimes I do not have all the Civs I have met shown. Sometimes, only 1 or 2 are shown and sometimes, they are all shown. Is there something I am missing in getting all the Civs to show up on that screen? I find the Power graph most useful of all and rely on it.

You must have enough espionnage point against that civ. Once you reach the recquired espionnage point with that civ, youll get to see is graph. Its called passive effect or something.

I thank you for the answer. This has been bugging me for a long time.